The invention has been devised primarily (though not exclusively) in the context of relatively large buildings such as commercial greenhouses, for example, for use at retail garden centres. Typically, a garden centre will have a building which serves both to provide a growing environment for plants, and as retail space in which the plants are displayed to customers for sale. As such, the building may be essentially a large greenhouse, but one that can be opened up to the outside to provide good access to customers. Ideally, a side wall of the greenhouse is provided with large doors that can be opened up during the day so that the interior space within the building becomes part of the outdoors.
Traditional techniques for addressing this objective involve the use of sliding door systems or accordion doors that fold back to the sides of the door opening. Both of these expedients have a number of disadvantages. Sliding door systems require extra space within adjacent walls for storing the panels when the door is open. Also, a track or threshold is required at ground level to guide the panels. This can represent an obstruction to traffic through the door when it is open, or at least a maintenance item. Accordion doors that fold back to the sides of the opening normally do not have to be accommodated within adjacent walls, but the folded panels do obstruct at the sides of the opening.
An object of the present invention is to provide a curtain wall structure which is capable of being opened and which avoids these disadvantages of the prior art.